title: Angle-dependent decoherence of charge qubits in free-standing slabs.
abstract: We investigate the decoherence of a charge qubit in a double quantum dot which is formed in a free-standing semiconductor slab. The dots are spatially arranged to align along a particular direction. Confined phonons in the slab have a remarkable influence on the dynamics of a qubit system. We show that the decoherence of such a qubit strongly depends on the positions of the dots. By varying the tunnel coupling, the decoherence differs significantly in laterally and vertically coupled quantum dots. A robust qubit is further achieved due to suppression of electron-phonon coupling. Moreover, the coherent evolution of the system is analyzed by modulating the interdot direction.
authors.affiliation: Department of Applied Physics, National University of Kaohsiung, Kaohsiung, Taiwan. yyliao@nuk.edu.tw
authors.forename: Ying-Yen
authors.initials: YY
authors.lastname: Liao
authors.forename: Yueh-Nan
authors.initials: YN
authors.lastname: Chen
authors.forename: Sheng-Rui
authors.initials: SR
authors.lastname: Jian